i got home after 2 days of no attention and sadly failed to take a foto of the green scummy surface that had appeared. starting and running the filter just gave the pool a nasty cloud that otherwise didn't fix quickly. a trip to the pool shop has lead me to 'flock' the pool. this means brushing the sides down, tipping 10l of liquid chlorine in, and then tipping 1L of this 'floke'ing agent in. the waiting. then when it sinks to the bottom, i am going to vacum, with the filter set to 'waste' which should both empty and flush the small particles in the pool.